Mesenchymal stem cells, or MSCs, are multipotent stromal cells that have potential to differentiate into mesenchymal cell types, e.g. adipocytes, chondrocytes and osteocytes. MSCs have a great capacity for self-renewal while maintaining their multipotency. Bone marrow MSCs are currently being applied in clinical trials for a variety of treatments. Procedures for isolating, purifying, and replicating MSCs in culture are well known in the art.
MSCs can be cultured using beads, in monolayer (i.e. two-dimensions) or three-dimensional systems. These standard methods enable the growth of MSCs in conditions closely resembling their physiological environments. It has been documented that MSC behavior can vary between in vivo and in vitro settings. The differences between varying MSC lines have typically been attributed to differences in isolation techniques and in vitro culture conditions. For example, variation in growth conditions can impact cell behavior in vitro, including impacting the expression of cell surface markers. The expression of specific markers on the surfaces of cells can be used to differentiate between varying cell lines or to confirm the lineage of the cell line.
All cells (including MSCs) produce biological products during culture. For example, MCS's are known to produce over 200 unique proteins during culture. The specific biological products produced by MSCs during culture can be used to characterize and distinguish between various MSCs. However, even when MSCs from the same source are used, differences in isolation techniques and in vitro culture conditions can impact and change the production of secreted biological products. Of course, it is also known that deviations from the ideal cell growth conditions can lead to senescence and loss of culture.